Washing machine with reduced vibration

ABSTRACT

Washing machine including a cabinet forming an outside shape of the washing machine, legs fitted to a bottom of the cabinet for supporting the cabinet, and leg pads joined to an underside of the legs respectively for attenuating vibration taken place when the washing machine is operated, wherein the leg pad is formed of block copolymer of hard blocks and soft blocks, thereby attenuating vibration.

[0001] This application claims the benefit of the Korean ApplicationNos. P2003-0024734 filed on Apr. 18, 2003, P2003-0060269 filed on Aug.29, 2003, and P2003-0060270 filed on Aug. 29, 2003, which are herebyincorporated by reference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to washing machines, and moreparticularly, to a washing machine which can attenuates vibration duringoperation of the washing machine effectively.

[0004] 2. Background of the Related Art

[0005] The washing machines, for removing contaminants from laundry byapplying energy such as impact, have pulsator washing machines, drumwashing machines, and agitator washing machine depending on methods forapplying energy to the laundry. The drum washing machine rotates a drumto drop the laundry and give impact to the laundry mostly, to whichdetergent is added to make washing done. The pulsator, or the agitatorwashing machine gives impact to the laundry by means of rotatingpulsator or agitator connected to a washing shaft vertically mounted ina washing tub, to which detergent is added to make washing done.

[0006] That is, the washing machines wash laundry by giving impact tothe laundry mostly with mechanical means, for which the washing tub ordrum, or the like where the laundry is placed is rotated, that causes ingeneral vibration. According to this, the washing machines are providedwith different vibration attenuation means.

[0007] Before starting description of a related art vibrationattenuating method, as an example of a related art washing machine, thedrum washing machine will be described with reference to FIGS. 1 and 2.

[0008] A cabinet 3, a body of the washing machine, is provided with afront portion 34, side portions 32, an upper cover 38, and a lower base36. The front portion 34 of the cabinet has a door 4 mounted to beopened/closed, and the base 36 has legs 5 for supporting the washingmachine on a floor the washing machine is installed thereon.

[0009] The cabinet 3 has a tub 7 for holding washing water, having adrum 9 rotatably mounted therein for placing laundry therein. The drum 9has a motor 11 connected thereto for generating a driving force torotate the drum 9.

[0010] In the meantime, upon putting the washing machine into operation,the drum 9 rotates at a high speed, according to which vibration istaken place. Particularly, since the drum 9 rotates at a high speed in aspinning cycle, the vibration is heavy. According to this, differentkinds of means are provided to the washing machine for reducinggeneration of vibration or attenuation of generated vibration.

[0011] For an example, for preventing and reducing transmission of thevibration from the drum 9 to the cabinet 3, and the like, there aresprings 13 between the tub 7 and the upper cover 38, and dampers 15between the tub 7 and the base 36. Moreover, material or thickness ofthe side portions 32 and/or base 36 of the cabinet 3 are adjusted, orbeads 32 a are formed at the side portions 32 of the cabinet 3. Asillustrated in FIG. 3 in detail, a leg pad 17 of a material that canattenuate vibration is fitted to the leg 5.

[0012] However, the related art vibration attenuating method and awashing machine thereof has the following problems.

[0013] First, correlations between the different kinds of vibrationattenuating means have not been clear, to cause a limit in reducing thevibration in an overall point of view, effectively.

[0014] Second, effective attenuation of the vibration over all ranges ofrotating speed of drum or the motor of the washing machine has beendifficult. For an example, if a damping forces of the dampers aredesigned higher for attenuation of transient vibration mostly caused bynon-uniform distribution of the laundry when proceeding into a spinningcycle, the vibration becomes heavier in a rated spinning speed to thecontrary, and opposite to this, if the damping forces are designedlower, the transient vibration takes place while the vibration at therated spinning speed is reduced. Moreover, also in the case of the legpad, since a range of the rotation speed of the washing machineeffective for attenuating the vibration is fixed substantially dependingon a material of the leg pad, it is difficult to attenuate vibrationeffectively over all ranges of rotation speed of the washing machine.

SUMMARY OF THE INVENTION

[0015] Accordingly, the present invention is directed to a washingmachine that substantially obviates one or more of the problems due tolimitations and disadvantages of the related art.

[0016] An object of the present invention is to provide a method foreffective attenuation of vibration of a washing machine, and a washingmachine thereof.

[0017] Another object of the present invention is to provide a methodfor effective attenuation of vibration of a washing machine, and awashing machine thereof, in which vibration attenuation is effectiveover all ranges of rotation speed of the washing machine.

[0018] Additional features and advantages of the invention will be setforth in the description which follows, and in part will be apparent tothose having ordinary skill in the art upon examination of the followingor may be learned from practice of the invention. The objectives andother advantages of the invention will be realized and attained by thestructure particularly pointed out in the written description and claimshereof as well as the appended drawings.

[0019] To achieve these objects and other advantages and in accordancewith the purpose of the present invention, as embodied and broadlydescribed herein, the washing machine includes a cabinet forming anoutside shape of the washing machine, legs fitted to a bottom of thecabinet for supporting the cabinet, and leg pads joined to an undersideof the legs respectively for attenuating vibration taken place when thewashing machine is operated, wherein the leg pad is formed of blockcopolymer of hard blocks and soft blocks.

[0020] The leg pad includes a first member in contact with a floorhaving the washing machine installed thereon, and a second member incontact with the first member, wherein, preferably, at least one of thefirst member and the second member is the block copolymer of hard blocksand soft blocks.

[0021] In the meantime, preferably, the hard block is a material whichmeets required mechanical properties, and the soft block is a materialwhich meets vibration attenuation characteristic. Preferably, the softblock has a glass transition temperature of room temperature, and morepreferably, −30° C.˜30° C.

[0022] In the meantime, preferably, the leg pad of the washing machineinstalled on a slippery floor has Shore hardness of approx. 80, andpreferably the leg pad of the washing machine installed on anon-slippery floor has Shore hardness of approx. 30.

[0023] In the meantime, preferably, the hard block is polystyrene, andthe soft block is polyisoprene, and more preferably, the soft block isvinyl-polyisoprene. The block copolymer is preferably blended with atleast one selected from olefin based thermo plastic resin, ethylene-αolefin copolymer, ethylene-vinylacetate copolymer,ethylene-ethylacrylrate copolymer, styrene-butadiene-styrene copolymer,and styrene-isoprene-styrene copolymer.

[0024] In other aspect of the present invention, there is provided awashing machine including a cabinet forming an outside shape of thewashing machine, a tub in the cabinet for holding washing water, a drumrotatably mounted in the tub, dampers fitted between a base of thecabinet and the tub for reducing transmission of vibration from thedrum, wherein the damper is coupled to the cabinet, with a first dampingmember in contact with the damper, and a second damping member incontact with the first damping member placed inbetween, and at least oneof the first damping member, and the second damping member is blockcopolymer of hard blocks and soft blocks.

[0025] Also, the hard block is a material which meets requiredmechanical properties, and the soft block is a material which meetsvibration attenuation characteristic.

[0026] Thus, the present invention can attenuate vibration generated atthe washing machine, effectively.

[0027] It is to be understood that both the foregoing description andthe following detailed description of the present invention areexemplary and explanatory and are intended to provide furtherexplanation of the invention claimed.

BRIEF DESCRITPION OF THE DRAWINGS

[0028] The accompanying drawings, which are included to provide afurther understanding of the invention and are incorporated in andconstitute a part of this application, illustrate embodiment (s) of theinvention and together with the description serve to explain theprinciple of the invention.

[0029] In the drawings;

[0030]FIG. 1 illustrates a perspective view of a related art drumwashing machine;

[0031]FIG. 2 illustrates a longitudinal section of FIG. 1;

[0032]FIG. 3 illustrates a side view of the leg in FIG. 1;

[0033]FIGS. 4 and 5 illustrate graphs each showing a principle andeffect of a washing machine with reduced vibration in accordance with apreferred embodiment of the present invention;

[0034]FIG. 6 illustrates a structure of a leg pad applicable to awashing machine with reduced vibration in accordance with a preferredembodiment of the present invention, schematically;

[0035]FIG. 7 illustrates a comparative graph of damping forces of theleg pads of the present invention and the related art;

[0036]FIG. 8 illustrates a disassembled perspective view of a leg and aleg pad in accordance with a preferred embodiment of the presentinvention;

[0037]FIG. 9 illustrates a side view of FIG. 8;

[0038]FIG. 10 illustrates a section of a leg and a leg pad in accordancewith another preferred embodiment of the present invention;

[0039]FIG. 11 illustrates a section of a leg and a leg pad in accordancewith still another preferred embodiment of the present invention;

[0040]FIG. 12 illustrates a section of a leg pad in accordance withanother preferred embodiment of the present invention;

[0041]FIG. 13 illustrates a section of a variation of FIG. 12;

[0042]FIGS. 14A and 14B illustrate a section and a plan view of a legpad in accordance with another preferred embodiment of the presentinvention, respectively;

[0043]FIGS. 15A and 15B illustrate a section and a plan view of avariation of FIGS. 14A or 14B;

[0044]FIGS. 16 and 17 illustrate sections each showing a leg pad inaccordance with another preferred embodiment of the present invention;and

[0045] FIGS. 18˜21 illustrate sections each showing a detail of a damperfastening portion in a washing machine with reduced vibration of thepresent invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0046] Reference will now be made in detail to the preferred embodimentsof the present invention, examples of which are illustrated in theaccompanying drawings.

[0047] A principle of a washing machine with a reduced vibration will bedescribed, with reference to FIGS. 4 and 5.

[0048] Of various methods for attenuating vibration, the inventor madestudy for finding out a most effective method for attenuating vibration.As a result, of various parameters, such as damper, material, thickness,and shape of the cabinet, and material of the leg pad, it finds out thatoptimization of the leg pad is the most effective for reduction of thevibration. Test results verifying that proper design of the leg pad isthe most effective for reduction of the vibration are illustrated inFIGS. 4 and 5.

[0049]FIGS. 4 and 5 illustrate graphs each showing principle and effectof a washing machine with reduced vibration in accordance with apreferred embodiment of the present invention. That is, vibrations ofdifferent washing machines (hereafter called as “samples”), in whichvarious parameters generally known to be effective for vibration arevaried, are measured in spinning processes in which vibration can causethe most serious problem, respectively. In the vibration measurement, a400 g of eccentricity is provided, and the vibration is measured at aright side upper comer ‘A’ and at a right side central portion ‘B’ ofthe cabinet with a vibration measuring apparatus (EQP/2).

[0050]FIG. 4 illustrates a test result at a right side portion of thecabinet, and FIG. 5 illustrates a test result at a left side portion ofthe cabinet. In FIGS. 4 and 5, A(Max) denotes a greatest vibrationmeasured at the upper comer, and A(Normal) denotes a normal vibrationmeasured at the upper comer. Alikely, B(Max) denotes a greatestvibration measured at the central portion, and B(Normal) denotes anormal vibration measured at the central portion.

[0051] It will be described in detail. Sample 1 denotes a drum washingmachine in which a 0.15 mm bead depth is added to a general bead depthformed at the side of the cabinet, and the leg pad is formed of butylrubber the same with the related art. Sample 1 a denotes the samewashing machine with sample 1, except that material of the leg pad isdifferent. Sample 2 denotes a drum washing machine in which no beaddepth is changed, or material of the leg pad is also the butyl rubber ofthe related art. Sample 2 a denotes a washing machine the same withsample 2, except that the material of the leg pad is different.

[0052] As the material for the leg pad used in sample 1 a and sample 2a, a material that shows the best result is used among many materialsthe inventor studied and tested. (the leg pad will be described indetail, later).

[0053]FIGS. 4 and 5 are analyzed as follows.

[0054] Upon reviewing test results of sample 1 and sample 2 of which legpads are the same, and bead depths only are different, it can be notedthat deeper bead depth is effective for attenuation of vibration forsome extent. However, it can be known that correlation between the beaddepth and the vibration attenuation is not clear.

[0055] However, upon reviewing test results of sample 1 and sample 1 a,or sample 2 and sample 2 a, of which bead depths are the same, and theleg pads are different, it can be noted that a proper leg pad is veryeffective for attenuating vibration.

[0056] Moreover, upon reviewing test results of sample 1 a and sample 2a, it can be known that optimization of the material of the leg pad ismore effective for vibration attenuation than the bead depth.

[0057] Therefore, for effective vibration attenuation, it is preferablethat the leg pad is designed the most properly.

[0058] As described above, it is preferable that the leg pad is designedthe most properly for effective vibration attenuation. Therefore, it ispreferable that, first of all, the most suitable leg pad, particularly,the most suitable material of the leg pad is used for attenuation of thevibration, and the other vibration attenuation parameters are taken intoconsideration. According to this, the inventor studied on the leg padsuitable for vibration attenuation further, to obtain the followingresults.

[0059] First of all, it is required that the leg pad has an excellentvibration attenuating characteristic. However, for use as the leg padactually, it is required to meet, not only the vibration attenuatingcharacteristic, but also other various conditions. For an example,conditions, such as mechanical properties, such as hardness, anti-slipproperty for preventing the washing machine from slipping from aninstalled place, formability representing easiness of fabrication, andthe like are required to be satisfied. Because, even if the vibrationattenuation characteristic is satisfied, if the material fails to have aproper hardness, resonance is occurred at a certain range of rotationspeed of the washing machine, to cause walking of the washing machine.If friction with the floor is not adequate, it is liable that thewashing machine slips on the floor.

[0060] At the end, even though it is required that the leg pad meetsabove different conditions in addition to the vibration attenuatingcharacteristic, selection of an optimal leg pad that meets aboveconditions substantially has been difficult in the related art.Accordingly, up to now, as the leg pad, metal, plastic,isobutylene-isoprene rubber, or the like is used, each of the materialhas advantages, and disadvantages. Even though metal or plastic, with acomparatively high hardness, has a resonance range outside of rotationspeed of the washing machine, it is liable that the leg pad of metal orplastic causes walking of washing machine in almost all ranges of therotation speed, regardless of the rotation range. Moreover, the leg padof metal or plastic is liable to cause slipping of the washing machinebecause the metal or plastic has low friction with the floor on whichthe washing machine is installed. In a case of the butyl rubber, sincethe butyl rubber has a resonance range in a low rotation speed range ofthe washing machine, it is required that the washing machine iscontrolled to pass the resonance range quickly, and the leg pad of thebutyl rubber is liable to cause walking of the washing machine in thelow rotation speed range, even though the walking is comparatively rarein a high rotation speed range.

[0061] As a result of study on the material of the leg pad for solvingabove problems, the inventor finds out that use of a block copolymer ofhard blocks and soft blocks is very effective as the material of the legpad. That is, as illustrated in FIG. 6, the inventor finds out that theleg pad is preferably formed of a copolymer in which the hard blocks HSand the soft blocks SS make a net form. Because the use of the leg padof the copolymer of the hard blocks HS and the soft blocks SS enables toselect a material that meets required mechanical properties, such ashardness, as the hard blocks, and a material that meets requiredvibration attenuation characteristic as the soft blocks. According tothis, the leg pad can be designed comparatively easily, that meets thevibration attenuation characteristics while other conditions are met.

[0062] In view of vibration attenuation, it is preferable that amaterial that has a glass transition is used as the block copolymer,particularly, the soft block, and more preferably, a material of whichglass transition temperature is close to a temperature of use of thewashing machine. Because, though thermal movement of chain form ofpolymers in the net becomes violent at a temperature higher than theglass transition temperature, to exhibit a rubbery state, the thermalmovement is suppressed at a temperature below the glass transitiontemperature, to become a glassy state due to reduction of its ownvolume, and have a poor vibration attenuation effect.

[0063] Since amorphous polymers, such as rubber, exhibit the glasstransition, it is preferable that rubber is selected as the leg pad. Thebutyl rubber used presently also exhibits the glass transition. However,as described before, though the leg pad is required to meet, not onlythe vibration attenuation characteristic, but also other properties,different from the block copolymer of the hard blocks and the softblocks of the present invention, the butyl rubber, a copolymer preparedby copolymerizing a small amount of isoprene with isobutylen, can notmeet other properties besides the vibration attenuation characteristic.In view of the vibration attenuation characteristic, it is difficult toobtain the desired adequate vibration attenuation effect because thebutyl rubber has a glass transition temperature in a range of −40°C.˜−60° C., which is substantially low than the temperature of use ofthe washing machine. As shown in FIG. 7, in a case of the butyl rubber,though the butyl rubber has a uniform damping force in a temperaturerange of use of the washing machine substantially, in an actualtemperature range of use of the washing machine, the damping force ofthe leg pad of the butyl rubber is poorer than the leg pad of the blockcopolymer of the present invention.

[0064] As described, preferably, the leg pad of the present invention isformed of a block copolymer of hard blocks and soft blocks, wherein thehard blocks are selected in mechanical point of view, and the softblocks are selected in view of vibration attenuation.

[0065] Accordingly, it is preferable that a material is selected as thesoft block, of which glass transition temperature is in the vicinity ofthe temperature of use of the washing machine. Of course, it ispreferable that a material is selected as the hard blocks in view ofrequirements of mechanical properties, such as hardness. For an example,in a case of washing machine installed on a slippery floor of cement ortile, it is favorable that a hardness of the leg pad is high. Ingeneral, it is preferable that Shore hardness is approx. 80. Opposite tothis, in a case of floor of wood, it is preferable that the hardness islow, in general, approx. 30 in Shore A hardness.

[0066] As a result of test on various materials, the inventor finds outthat the hard block is polystyrene, and the soft block is polyisoprene,particularly, vinyl-polyisoprene.

[0067] In fabrication of the leg pad, though the block copolymer may beused solely, at least one selected from olefin based thermo plasticresin, ethylene-α olefin copolymer, ethylene-vinylacetate copolymer,ethylene-ethylacrylrate copolymer, styrene-butadiene-styrene copolymer,and styrene-isoprene-styrene copolymer may be blended with the blockcopolymer. Moreover, additives, such as cross-linker, filler, andsoftner, may be introduced into a base material of the block copolymer,that is known to a person skilled in the field of art, of which detaileddescription will be omitted.

[0068] As described, the leg pad of the block copolymer of hard blockand soft block enables to fabricate a leg pad that satisfies thevibration attenuation characteristic and other required properties verymuch.

[0069] In order to verify this, a test is carried out on a material thatsubstantially satisfies above conditions among commercially availablematerials. The material used in the test is Kuraray Hybrar. The Hybrar,a block copolymer of polystyrene and polyisoprene, has a glasstransition temperature in the vicinity of room temperature of approx.−19° C.˜−8° C. As shown in FIG. 7, it is verified that the leg pad ofthe Hybrar has very good damping force in the vicinity of roomtemperature. In FIG. 4 or 5, the material of the leg pad in the sample 1a and the sample 2 a is Hybrar. Of course, the material suitable for theleg pad is not limited to Hybrar, and any material that satisfies aboveconditions can be used.

[0070] In the meantime, as described, it is preferable that the leg padhas, not only an excellent vibration attenuation characteristic, butalso excellent formability and workability taking production cost of thewashing machine into consideration. Hybrar has a better anti-slipcharacteristic than butyl rubber, and particularly, has a good frictioneven in a watery environment compared to other rubbers. Moreover, sincethe Hybrar can be used as a thermoplastic resin that can be injectionmolded or extrusion molded, or thermosetting resin that can be pressed,the Hybrar also has an advantage of good formability. However, if it isintended to use the Hybrar as the thermosetting resin, a separatecross-linker is required.

[0071] In the meantime, referring to FIG. 8, the leg is joined to theleg pad by a predetermined method. Examples of preferable joining of theleg and the leg pad will be described with reference to FIGS. 8˜11.

[0072] First, the leg will be described. In general, the leg 5 includesa cylindrical body 52, and a head 54 at a bottom end of the body 52. Itis preferable that the body 52 has a thread formed therein for easyadjustment of a height. The head 54 is used for easy turning of the body52 with a thread, to make adjustment of the height easy.

[0073] In the meantime, the leg pad 17 is fitted to a bottom end of theleg 5. Though the leg pad 17 may be fitted to the head 54 of the leg 5directly, it is preferable that an enlarged portion 56 may be furtherformed in a lower portion of the head 54 for securing a fitting area,and easy fitting.

[0074] The leg 5 and the leg pad 17 may be joined by insert molding,bonding, or other methods. For an example, as shown in FIG. 9, the leg 5and the leg pad 17 may be joined with an adhesive. Or, as shown in FIG.10, the leg 5 and the leg pad 17 may be joined by insert molding. Or, asshown in FIG. 11, a recess 17 a having a portion of a lower portion ofthe leg pad 17 cut away therefrom in a circumferential direction may beformed, and the leg 5 and the leg pad 17 may be joined with an elastichook 19 that surrounds the enlarged portion 56 of the leg and the recess17 a in the leg pad 17.

[0075] In the meantime, though a leg pad formed of one material, i.e.,the block copolymer is described in above embodiment, as a result ofstudy of the inventor, it is found out that it is possible to form theleg pad of more than two materials. That is, it is preferable that theleg pad is formed of a first member in contact with a floor the washingmachine is installed thereon, and a second member in contact with thefirst member, and one of the first, and second members is formed ofblock copolymer, and the other one is formed of other material, such asbutyl rubber. Because above material of the leg pad, i.e., the blockcopolymer of the hard blocks, and the soft blocks may cause plasticdeformation after a certain time period, to have a poor vibrationattenuation effect. Particularly, the vibration attenuation effect canbecome poor in a low temperature range.

[0076] Another embodiment of the leg pad of the present invention willbe described, with reference to FIGS. 12 to 17.

[0077] Referring to FIG. 12, the leg pad 17 includes a first member 17 ain contact with a floor having the washing machine installed thereon,and a second member 17 b fitted to the first member 17 a, wherein it ispreferable that one of the first member 17 a and the second member 17 bis formed of butyl rubber, and the other one is formed of blockcopolymer. For the sake of description, a right side upward hatching(for an example, a reference symbol 17 b in FIG. 12) denotes that thematerial is block copolymer, and the other mark on the section (for anexample, a reference symbol 17 a in FIG. 12) denotes that the materialis butyl rubber.

[0078] Referring to FIG. 12, though the first member 17 a may be formedof butyl rubber, and the second member 17 b may be formed of blockcopolymer, as shown in FIG. 13, it is more preferable that the firstmember 17 a is formed of block copolymer, and the second member 17 b isformed of butyl rubber. Because the block copolymer has better contactwith the floor, it is favorable that the first member 17 a is formed ofthe block copolymer.

[0079] In the meantime, referring to FIGS. 14A and 14B, the first member17 a may have a projection 170 having the second member 17 b passedthrough. Or, as shown in FIGS. 15A and 15B, the first member 17 a mayhave a plurality of projections 170 having the second member 17 b passedthrough.

[0080] Or, referring to FIGS. 16 and 17, a third member 17 c of amaterial the same with the first member 17 a may be fitted to top of thesecond member 17 b.

[0081] In the meantime, the first member 17 a, the second member 17 b,and the third member 17 c may be joined by bonding, or double injectionmolding, and the leg pad 17 and the leg may be joined by bonding, insertmolding, or mechanical joining, as described before.

[0082] In the meantime, in the study of the inventor, it finds out thatthe principle of the present invention is applicable not only to theleg, but also to other components, used in the washing machine and thelike as a vibration attenuator. Particularly, it is preferable that theprinciple of the present invention is applied to the damper fittedbetween the base of the cabinet and the tub for preventing vibration ofthe washing machine and the like from transmitting to the cabinet.

[0083] The application of the principle of the present invention to thedamper of the drum washing machine will be described with reference toFIG. 18.

[0084] One end of the damper 15 is fixed to the base 36 with a dampingmember 100 placed in between. In this instance, though the dampingmember 100 may be formed of one material solely, i.e., the blockcopolymer, as a result of study of the inventor, it is found out that itis possible to form the damping member 100 of the present invention ofmore than two materials, for an example, one is formed of blockcopolymer, and the other one is formed of other material, such as butylrubber. Because the block copolymer of the hard blocks, and the softblocks may cause plastic deformation after a certain time period, tohave a poor vibration attenuation effect. Particularly, the vibrationattenuation effect can become poor in a low temperature range.

[0085] It will be described in more detail. For the sake of description,a right side upward hatching (for an example, a reference symbol 120 inFIGS. 18˜21) denotes that the material is block copolymer, and the othermark on the section (for an example, a reference symbol 110 in FIGS.18˜21) denotes that the material is butyl rubber.

[0086] Referring to FIG. 18, the damper 15 is fixed to the base 36 witha first damping member 110 in contact with the damper 15, and a seconddamping member 120 in contact with the first damping member 110 placedinbetween, wherein one of the first damping member 110 and the seconddamping member 120 is a block copolymer of hard blocks and soft blocks.

[0087] In more detail, the damper 15 has a hollow coupling portion 15 aat one end (a portion near to the base of cabinet). The coupling portion15 a has a cylindrical first damping member 110 fitted therein, and acylindrical second damping member 120 is fitted in the hollow of thefirst damping member 110. There is a bracket 16 fixed to the base 36,having one side opened to a damper direction.

[0088] That is, the coupling portion 15 a of the damper 15, the firstdamping member 110, and the second damping member 120 are positioned inthe opening of the bracket 16, and, under this state, a bolt 16 a ispassed through the bracket 16, and the second damping member 120, tohave the damper 15 fitted between the tub and the cabinet.

[0089] In the meantime, referring to FIG. 18, it is also possible thatthe first damping member 110 is formed of butyl rubber, and the seconddamping member 120 is formed of block copolymer. However, as shown inFIG. 19, it is preferable that the first damping member 110 is formed ofthe block copolymer, and the second damping member 120 is formed ofbutyl rubber, because it is favorable in view of vibration attenuationthat the first damping member 110 that comes into contact with thedamper 15 at first is formed of the block copolymer.

[0090] Moreover, referring to FIGS. 20 and 21, it may also possible thata third damping member 130 formed of a material the same with thematerial of the first damping member 110 is fitted on an inside of thesecond damping member 120. Of course, it is also possible that the thirddamping member 130 formed of a material the same with the material ofthe second damping member 120 is fitted on an outside of the firstdamping member 110.

[0091] In the meantime, besides that the first damping member 110, thesecond damping member 120, and the third damping member 130 may bejoined by bonding or double injection molding, the components may bejoined by other methods, of which detail will be omitted.

[0092] Though a drum washing machine is illustrated and described inabove embodiments, the present invention is not limited to this. Thatis, the present invention is applicable to the pulsator washing machine,and the agitator washing machine, too. Moreover, the present inventionis applicable, not only to a leg joined to the cabinet, a body, but alsoto other components that are used for attenuation of vibration in thewashing machine.

[0093] It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the invention. Thus, it isintended that the present invention cover the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

[0094] As has been described, the method for attenuating vibration of awashing machine, and a washing machine thereof has the followingadvantages.

[0095] First, vibration can be attenuated effectively by selecting theleg pads, properly. That is, vibration of the washing machine can bereduced effectively while changes in design, and a cabinet material,thickness, and bead depth that causes a production cost increases areminimized. That is, by proper selection of the damping member of thedamper, and the leg pad of which design and effect verification arecomparatively easy, the vibration can be attenuated very effectively.

[0096] Second, the present invention permits to select a leg pad, whichmeets not only the vibration attenuation characteristic, but also othernecessary properties, such as hardness, and anti-slip characteristic, atthe same time, thereby permitting to make a washing machine designeffective in vibration attenuation over all ranges of rotation speed ofthe washing machine.

What is claimed is:
 1. A washing machine comprising: a cabinet formingan outside shape of the washing machine; legs fitted to a bottom of thecabinet for supporting the cabinet; and leg pads joined to an undersideof the legs respectively for attenuating vibration taken place when thewashing machine is operated, wherein the leg pad is formed of blockcopolymer of hard blocks and soft blocks.
 2. The washing machine asclaimed in claim 1, wherein the leg pad includes; a first member incontact with a floor having the washing machine installed thereon, and asecond member in contact with the first member, wherein at least one ofthe first member and the second member is the block copolymer of hardblocks and soft blocks.
 3. The washing machine as claimed in claim 2,wherein the hard block is a material which meets required mechanicalproperties, and the soft block is a material which meets vibrationattenuation characteristic.
 4. The washing machine as claimed in claim2, wherein the soft block has a glass transition temperature of roomtemperature.
 5. The washing machine as claimed in claim 4, wherein theglass transition temperature is −30° C.˜30° C.
 6. The washing machine asclaimed in claim 3, wherein the leg pad of the washing machine installedon a slippery floor has Shore hardness of approx.
 80. 7. The washingmachine as claimed in claim 3, wherein the leg pad of the washingmachine installed on a non-slippery floor has Shore hardness of approx.30.
 8. The washing machine as claimed in claim 3, wherein the hard blockis polystyrene, and the soft block is polyisoprene.
 9. The washingmachine as claimed in claim 3, wherein the soft block isvinyl-polyisoprene.
 10. The washing machine as claimed in claim 9,wherein the block copolymer is blended with at least one selected fromolefin based thermo plastic resin, ethylene-α olefin copolymer,ethylene-vinylacetate copolymer, ethylene-ethylacrylrate copolymer,styrene-butadiene-styrene copolymer, and styrene-isoprene-styrenecopolymer.
 11. The washing machine as claimed in claim 3, wherein theleg and the leg pad are bonded with an adhesive.
 12. The washing machineas claimed in claim 3, wherein the leg and the leg pad are joined byinsert molding.
 13. The washing machine as claimed in claim 3, whereinthe leg and the leg pad are joined by elastic hook.
 14. The washingmachine as claimed in claim 2, wherein the first member has at least oneprojection passed through the second member.
 15. The washing machine asclaimed in claim 2, wherein the second member has a third member incontact therewith, of a material the same with the first member.
 16. Awashing machine comprising: a cabinet forming an outside shape of thewashing machine; a tub in the cabinet for holding washing water; a drumrotatably mounted in the tub; dampers fitted between a base of thecabinet and the tub for reducing transmission of vibration from thedrum, wherein the damper is coupled to the cabinet, with a first dampingmember in contact with the damper, and a second damping member incontact with the first damping member placed inbetween, and at least oneof the first damping member, and the second damping member is blockcopolymer of hard blocks and soft blocks.
 17. The washing machine asclaimed in claim 16, wherein the second damping member has a thirddamping member in contact therewith, of a material the same with thefirst damping member.
 18. The washing machine as claimed in claim 16,wherein the hard block is a material which meets required mechanicalproperties, and the soft block is a material which meets vibrationattenuation characteristic.
 19. The washing machine as claimed in claim18, wherein the soft block has a glass transition temperature of roomtemperature.
 20. The washing machine as claimed in claim 19, wherein theglass transition temperature is −30° C.˜30° C.
 21. The washing machineas claimed in claim 18, wherein the hard block is polystyrene, and thesoft block is polyisoprene.
 22. The washing machine as claimed in claim21, wherein the soft block is vinyl-polyisoprene.
 23. The washingmachine as claimed in claim 21, wherein the block copolymer is blendedwith at least one selected from olefin based thermo plastic resin,ethylene-a olefin copolymer, ethylene-vinylacetate copolymer,ethylene-ethylacrylrate copolymer, styrene-butadiene-styrene copolymer,and styrene-isoprene-styrene copolymer.